我市的前三岛是众多海钓人的梦想之地.小明的爸爸周末去前三岛钓鱼,将鱼竿AB摆成如图1所示.已知AB=4.8 m,鱼竿尾端A离岸边0.4 m,即 AD=0.4 m.海面与地面AD平行且相距1.2 m,即DH=1.2 m.
(1)如图1,在无鱼上钩时,海面上方的鱼线BC与海面HC 的夹角∠BCH=37°,海面下方的鱼线CO与海面HC垂直,鱼竿AB与地面AD的夹角∠BAD=22°.求点О到岸边DH的距离;
(2)如图2,在有鱼上钩时,鱼竿与地面的夹角LBAD=53°,此时鱼线被拉直,鱼线BO=5.46 m,点О恰好位于海面.求点О到岸边DH的距离.
Dogs are the best pets of humans. They come in all sizes. Some dogs are as small as a football, and others are as tall as a desk. Dogs’ fur (毛) is different, too. It can be long and soft, or smooth and hard. People don’t mind the kind of fur, because all dogs are good to hug.
请在字典中查一下这个词。
我喜欢甜食， 你知道的。
去年， 彼得在旅途中和许多人交了朋友。
我叫托尼· 史密斯， 史密斯是我的姓。
我们在课上回答问题时应该起立
Tea and coffee are two of the most popular drinks in the world. However, people usually like one more than the other. These drinks also have very different uses.
People in the office usually sit for most of the day when they work. But this is bad for a person’s health. When people sit for too long every day, they don’t move very much. So it is easy to start getting fat. Sitting too long is also bad for their work because it makes them want to sleep. When this happens, people may make more mistakes in their work or spend more time finishing their work. Companies need workers to be healthy, so how do they fix the problem?
